text: /*
   * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   */
  #include <linux/list_sort.h>
  #include <linux/libnvdimm.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/ndctl.h>
  #include <linux/delay.h>
  #include <linux/list.h>
  #include <linux/acpi.h>
  #include <linux/sort.h>
  #include <linux/pmem.h>
  #include <linux/io.h>
  #include <asm/cacheflush.h>
  #include "nfit.h"
  
  /*
   * For readq() and writeq() on 32-bit builds, the hi-lo, lo-hi order is
   * irrelevant.
   */
  #include <linux/io-64-nonatomic-hi-lo.h>
  
  static bool force_enable_dimms;
  module_param(force_enable_dimms, bool, S_IRUGO|S_IWUSR);
  MODULE_PARM_DESC(force_enable_dimms, "Ignore _STA (ACPI DIMM device) status");
  
  struct nfit_table_prev {
  	struct list_head spas;
  	struct list_head memdevs;
  	struct list_head dcrs;
  	struct list_head bdws;
  	struct list_head idts;
  	struct list_head flushes;
  };
  
  static u8 nfit_uuid[NFIT_UUID_MAX][16];
  
  const u8 *to_nfit_uuid(enum nfit_uuids id)
  {
  	return nfit_uuid[id];
  }
  EXPORT_SYMBOL(to_nfit_uuid);
  
  static struct acpi_nfit_desc *to_acpi_nfit_desc(
  		struct nvdimm_bus_descriptor *nd_desc)
  {
  	return container_of(nd_desc, struct acpi_nfit_desc, nd_desc);
  }
  
  static struct acpi_device *to_acpi_dev(struct acpi_nfit_desc *acpi_desc)
  {
  	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
  
  	/*
  	 * If provider == 'ACPI.NFIT' we can assume 'dev' is a struct
  	 * acpi_device.
  	 */
  	if (!nd_desc->provider_name
  			|| strcmp(nd_desc->provider_name, "ACPI.NFIT") != 0)
  		return NULL;
  
  	return to_acpi_device(acpi_desc->dev);
  }
  
  static int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc,
  		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
  		unsigned int buf_len)
  {
  	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
  	const struct nd_cmd_desc *desc = NULL;
  	union acpi_object in_obj, in_buf, *out_obj;
  	struct device *dev = acpi_desc->dev;
  	const char *cmd_name, *dimm_name;
  	unsigned long dsm_mask;
  	acpi_handle handle;
  	const u8 *uuid;
  	u32 offset;
  	int rc, i;
  
  	if (nvdimm) {
  		struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
  		struct acpi_device *adev = nfit_mem->adev;
  
  		if (!adev)
  			return -ENOTTY;
  		dimm_name = nvdimm_name(nvdimm);
  		cmd_name = nvdimm_cmd_name(cmd);
  		dsm_mask = nfit_mem->dsm_mask;
  		desc = nd_cmd_dimm_desc(cmd);
  		uuid = to_nfit_uuid(NFIT_DEV_DIMM);
  		handle = adev->handle;
  	} else {
  		struct acpi_device *adev = to_acpi_dev(acpi_desc);
  
  		cmd_name = nvdimm_bus_cmd_name(cmd);
  		dsm_mask = nd_desc->dsm_mask;
  		desc = nd_cmd_bus_desc(cmd);
  		uuid = to_nfit_uuid(NFIT_DEV_BUS);
  		handle = adev->handle;
  		dimm_name = "bus";
  	}
  
  	if (!desc || (cmd && (desc->out_num + desc->in_num == 0)))
  		return -ENOTTY;
  
  	if (!test_bit(cmd, &dsm_mask))
  		return -ENOTTY;
  
  	in_obj.type = ACPI_TYPE_PACKAGE;
  	in_obj.package.count = 1;
  	in_obj.package.elements = &in_buf;
  	in_buf.type = ACPI_TYPE_BUFFER;
  	in_buf.buffer.pointer = buf;
  	in_buf.buffer.length = 0;
  
  	/* libnvdimm has already validated the input envelope */
  	for (i = 0; i < desc->in_num; i++)
  		in_buf.buffer.length += nd_cmd_in_size(nvdimm, cmd, desc,
  				i, buf);
  
  	if (IS_ENABLED(CONFIG_ACPI_NFIT_DEBUG)) {
  		dev_dbg(dev, "%s:%s cmd: %s input length: %d\n", __func__,
  				dimm_name, cmd_name, in_buf.buffer.length);
  		print_hex_dump_debug(cmd_name, DUMP_PREFIX_OFFSET, 4,
  				4, in_buf.buffer.pointer, min_t(u32, 128,
  					in_buf.buffer.length), true);
  	}
  
  	out_obj = acpi_evaluate_dsm(handle, uuid, 1, cmd, &in_obj);
  	if (!out_obj) {
  		dev_dbg(dev, "%s:%s _DSM failed cmd: %s\n", __func__, dimm_name,
  				cmd_name);
  		return -EINVAL;
  	}
  
  	if (out_obj->package.type != ACPI_TYPE_BUFFER) {
  		dev_dbg(dev, "%s:%s unexpected output object type cmd: %s type: %d\n",
  				__func__, dimm_name, cmd_name, out_obj->type);
  		rc = -EINVAL;
  		goto out;
  	}
  
  	if (IS_ENABLED(CONFIG_ACPI_NFIT_DEBUG)) {
  		dev_dbg(dev, "%s:%s cmd: %s output length: %d\n", __func__,
  				dimm_name, cmd_name, out_obj->buffer.length);
  		print_hex_dump_debug(cmd_name, DUMP_PREFIX_OFFSET, 4,
  				4, out_obj->buffer.pointer, min_t(u32, 128,
  					out_obj->buffer.length), true);
  	}
  
  	for (i = 0, offset = 0; i < desc->out_num; i++) {
  		u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i, buf,
  				(u32 *) out_obj->buffer.pointer);
  
  		if (offset + out_size > out_obj->buffer.length) {
  			dev_dbg(dev, "%s:%s output object underflow cmd: %s field: %d\n",
  					__func__, dimm_name, cmd_name, i);
  			break;
  		}
  
  		if (in_buf.buffer.length + offset + out_size > buf_len) {
  			dev_dbg(dev, "%s:%s output overrun cmd: %s field: %d\n",
  					__func__, dimm_name, cmd_name, i);
  			rc = -ENXIO;
  			goto out;
  		}
  		memcpy(buf + in_buf.buffer.length + offset,
  				out_obj->buffer.pointer + offset, out_size);
  		offset += out_size;
  	}
  	if (offset + in_buf.buffer.length < buf_len) {
  		if (i >= 1) {
  			/*
  			 * status valid, return the number of bytes left
  			 * unfilled in the output buffer
  			 */
  			rc = buf_len - offset - in_buf.buffer.length;
  		} else {
  			dev_err(dev, "%s:%s underrun cmd: %s buf_len: %d out_len: %d\n",
  					__func__, dimm_name, cmd_name, buf_len,
  					offset);
  			rc = -ENXIO;
  		}
  	} else
  		rc = 0;
  
   out:
  	ACPI_FREE(out_obj);
  
  	return rc;
  }
  
  static const char *spa_type_name(u16 type)
  {
  	static const char *to_name[] = {
  		[NFIT_SPA_VOLATILE] = "volatile",
  		[NFIT_SPA_PM] = "pmem",
  		[NFIT_SPA_DCR] = "dimm-control-region",
  		[NFIT_SPA_BDW] = "block-data-window",
  		[NFIT_SPA_VDISK] = "volatile-disk",
  		[NFIT_SPA_VCD] = "volatile-cd",
  		[NFIT_SPA_PDISK] = "persistent-disk",
  		[NFIT_SPA_PCD] = "persistent-cd",
  
  	};
  
  	if (type > NFIT_SPA_PCD)
  		return "unknown";
  
  	return to_name[type];
  }
  
  static int nfit_spa_type(struct acpi_nfit_system_address *spa)
  {
  	int i;
  
  	for (i = 0; i < NFIT_UUID_MAX; i++)
  		if (memcmp(to_nfit_uuid(i), spa->range_guid, 16) == 0)
  			return i;
  	return -1;
  }
  
  static bool add_spa(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_system_address *spa)
  {
  	size_t length = min_t(size_t, sizeof(*spa), spa->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_spa *nfit_spa;
  
  	list_for_each_entry(nfit_spa, &prev->spas, list) {
  		if (memcmp(nfit_spa->spa, spa, length) == 0) {
  			list_move_tail(&nfit_spa->list, &acpi_desc->spas);
  			return true;
  		}
  	}
  
  	nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa), GFP_KERNEL);
  	if (!nfit_spa)
  		return false;
  	INIT_LIST_HEAD(&nfit_spa->list);
  	nfit_spa->spa = spa;
  	list_add_tail(&nfit_spa->list, &acpi_desc->spas);
  	dev_dbg(dev, "%s: spa index: %d type: %s\n", __func__,
  			spa->range_index,
  			spa_type_name(nfit_spa_type(spa)));
  	return true;
  }
  
  static bool add_memdev(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_memory_map *memdev)
  {
  	size_t length = min_t(size_t, sizeof(*memdev), memdev->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_memdev *nfit_memdev;
  
  	list_for_each_entry(nfit_memdev, &prev->memdevs, list)
  		if (memcmp(nfit_memdev->memdev, memdev, length) == 0) {
  			list_move_tail(&nfit_memdev->list, &acpi_desc->memdevs);
  			return true;
  		}
  
  	nfit_memdev = devm_kzalloc(dev, sizeof(*nfit_memdev), GFP_KERNEL);
  	if (!nfit_memdev)
  		return false;
  	INIT_LIST_HEAD(&nfit_memdev->list);
  	nfit_memdev->memdev = memdev;
  	list_add_tail(&nfit_memdev->list, &acpi_desc->memdevs);
  	dev_dbg(dev, "%s: memdev handle: %#x spa: %d dcr: %d\n",
  			__func__, memdev->device_handle, memdev->range_index,
  			memdev->region_index);
  	return true;
  }
  
  static bool add_dcr(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_control_region *dcr)
  {
  	size_t length = min_t(size_t, sizeof(*dcr), dcr->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_dcr *nfit_dcr;
  
  	list_for_each_entry(nfit_dcr, &prev->dcrs, list)
  		if (memcmp(nfit_dcr->dcr, dcr, length) == 0) {
  			list_move_tail(&nfit_dcr->list, &acpi_desc->dcrs);
  			return true;
  		}
  
  	nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr), GFP_KERNEL);
  	if (!nfit_dcr)
  		return false;
  	INIT_LIST_HEAD(&nfit_dcr->list);
  	nfit_dcr->dcr = dcr;
  	list_add_tail(&nfit_dcr->list, &acpi_desc->dcrs);
  	dev_dbg(dev, "%s: dcr index: %d windows: %d\n", __func__,
  			dcr->region_index, dcr->windows);
  	return true;
  }
  
  static bool add_bdw(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_data_region *bdw)
  {
  	size_t length = min_t(size_t, sizeof(*bdw), bdw->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_bdw *nfit_bdw;
  
  	list_for_each_entry(nfit_bdw, &prev->bdws, list)
  		if (memcmp(nfit_bdw->bdw, bdw, length) == 0) {
  			list_move_tail(&nfit_bdw->list, &acpi_desc->bdws);
  			return true;
  		}
  
  	nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw), GFP_KERNEL);
  	if (!nfit_bdw)
  		return false;
  	INIT_LIST_HEAD(&nfit_bdw->list);
  	nfit_bdw->bdw = bdw;
  	list_add_tail(&nfit_bdw->list, &acpi_desc->bdws);
  	dev_dbg(dev, "%s: bdw dcr: %d windows: %d\n", __func__,
  			bdw->region_index, bdw->windows);
  	return true;
  }
  
  static bool add_idt(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_interleave *idt)
  {
  	size_t length = min_t(size_t, sizeof(*idt), idt->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_idt *nfit_idt;
  
  	list_for_each_entry(nfit_idt, &prev->idts, list)
  		if (memcmp(nfit_idt->idt, idt, length) == 0) {
  			list_move_tail(&nfit_idt->list, &acpi_desc->idts);
  			return true;
  		}
  
  	nfit_idt = devm_kzalloc(dev, sizeof(*nfit_idt), GFP_KERNEL);
  	if (!nfit_idt)
  		return false;
  	INIT_LIST_HEAD(&nfit_idt->list);
  	nfit_idt->idt = idt;
  	list_add_tail(&nfit_idt->list, &acpi_desc->idts);
  	dev_dbg(dev, "%s: idt index: %d num_lines: %d\n", __func__,
  			idt->interleave_index, idt->line_count);
  	return true;
  }
  
  static bool add_flush(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev,
  		struct acpi_nfit_flush_address *flush)
  {
  	size_t length = min_t(size_t, sizeof(*flush), flush->header.length);
  	struct device *dev = acpi_desc->dev;
  	struct nfit_flush *nfit_flush;
  
  	list_for_each_entry(nfit_flush, &prev->flushes, list)
  		if (memcmp(nfit_flush->flush, flush, length) == 0) {
  			list_move_tail(&nfit_flush->list, &acpi_desc->flushes);
  			return true;
  		}
  
  	nfit_flush = devm_kzalloc(dev, sizeof(*nfit_flush), GFP_KERNEL);
  	if (!nfit_flush)
  		return false;
  	INIT_LIST_HEAD(&nfit_flush->list);
  	nfit_flush->flush = flush;
  	list_add_tail(&nfit_flush->list, &acpi_desc->flushes);
  	dev_dbg(dev, "%s: nfit_flush handle: %d hint_count: %d\n", __func__,
  			flush->device_handle, flush->hint_count);
  	return true;
  }
  
  static void *add_table(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev, void *table, const void *end)
  {
  	struct device *dev = acpi_desc->dev;
  	struct acpi_nfit_header *hdr;
  	void *err = ERR_PTR(-ENOMEM);
  
  	if (table >= end)
  		return NULL;
  
  	hdr = table;
  	if (!hdr->length) {
  		dev_warn(dev, "found a zero length table '%d' parsing nfit\n",
  			hdr->type);
  		return NULL;
  	}
  
  	switch (hdr->type) {
  	case ACPI_NFIT_TYPE_SYSTEM_ADDRESS:
  		if (!add_spa(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_MEMORY_MAP:
  		if (!add_memdev(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_CONTROL_REGION:
  		if (!add_dcr(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_DATA_REGION:
  		if (!add_bdw(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_INTERLEAVE:
  		if (!add_idt(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_FLUSH_ADDRESS:
  		if (!add_flush(acpi_desc, prev, table))
  			return err;
  		break;
  	case ACPI_NFIT_TYPE_SMBIOS:
  		dev_dbg(dev, "%s: smbios\n", __func__);
  		break;
  	default:
  		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
  		break;
  	}
  
  	return table + hdr->length;
  }
  
  static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_mem *nfit_mem)
  {
  	u32 device_handle = __to_nfit_memdev(nfit_mem)->device_handle;
  	u16 dcr = nfit_mem->dcr->region_index;
  	struct nfit_spa *nfit_spa;
  
  	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
  		u16 range_index = nfit_spa->spa->range_index;
  		int type = nfit_spa_type(nfit_spa->spa);
  		struct nfit_memdev *nfit_memdev;
  
  		if (type != NFIT_SPA_BDW)
  			continue;
  
  		list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
  			if (nfit_memdev->memdev->range_index != range_index)
  				continue;
  			if (nfit_memdev->memdev->device_handle != device_handle)
  				continue;
  			if (nfit_memdev->memdev->region_index != dcr)
  				continue;
  
  			nfit_mem->spa_bdw = nfit_spa->spa;
  			return;
  		}
  	}
  
  	dev_dbg(acpi_desc->dev, "SPA-BDW not found for SPA-DCR %d\n",
  			nfit_mem->spa_dcr->range_index);
  	nfit_mem->bdw = NULL;
  }
  
  static void nfit_mem_init_bdw(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_mem *nfit_mem, struct acpi_nfit_system_address *spa)
  {
  	u16 dcr = __to_nfit_memdev(nfit_mem)->region_index;
  	struct nfit_memdev *nfit_memdev;
  	struct nfit_flush *nfit_flush;
  	struct nfit_bdw *nfit_bdw;
  	struct nfit_idt *nfit_idt;
  	u16 idt_idx, range_index;
  
  	list_for_each_entry(nfit_bdw, &acpi_desc->bdws, list) {
  		if (nfit_bdw->bdw->region_index != dcr)
  			continue;
  		nfit_mem->bdw = nfit_bdw->bdw;
  		break;
  	}
  
  	if (!nfit_mem->bdw)
  		return;
  
  	nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
  
  	if (!nfit_mem->spa_bdw)
  		return;
  
  	range_index = nfit_mem->spa_bdw->range_index;
  	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
  		if (nfit_memdev->memdev->range_index != range_index ||
  				nfit_memdev->memdev->region_index != dcr)
  			continue;
  		nfit_mem->memdev_bdw = nfit_memdev->memdev;
  		idt_idx = nfit_memdev->memdev->interleave_index;
  		list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
  			if (nfit_idt->idt->interleave_index != idt_idx)
  				continue;
  			nfit_mem->idt_bdw = nfit_idt->idt;
  			break;
  		}
  
  		list_for_each_entry(nfit_flush, &acpi_desc->flushes, list) {
  			if (nfit_flush->flush->device_handle !=
  					nfit_memdev->memdev->device_handle)
  				continue;
  			nfit_mem->nfit_flush = nfit_flush;
  			break;
  		}
  		break;
  	}
  }
  
  static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
  		struct acpi_nfit_system_address *spa)
  {
  	struct nfit_mem *nfit_mem, *found;
  	struct nfit_memdev *nfit_memdev;
  	int type = nfit_spa_type(spa);
  
  	switch (type) {
  	case NFIT_SPA_DCR:
  	case NFIT_SPA_PM:
  		break;
  	default:
  		return 0;
  	}
  
  	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
  		struct nfit_dcr *nfit_dcr;
  		u32 device_handle;
  		u16 dcr;
  
  		if (nfit_memdev->memdev->range_index != spa->range_index)
  			continue;
  		found = NULL;
  		dcr = nfit_memdev->memdev->region_index;
  		device_handle = nfit_memdev->memdev->device_handle;
  		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
  			if (__to_nfit_memdev(nfit_mem)->device_handle
  					== device_handle) {
  				found = nfit_mem;
  				break;
  			}
  
  		if (found)
  			nfit_mem = found;
  		else {
  			nfit_mem = devm_kzalloc(acpi_desc->dev,
  					sizeof(*nfit_mem), GFP_KERNEL);
  			if (!nfit_mem)
  				return -ENOMEM;
  			INIT_LIST_HEAD(&nfit_mem->list);
  			list_add(&nfit_mem->list, &acpi_desc->dimms);
  		}
  
  		list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
  			if (nfit_dcr->dcr->region_index != dcr)
  				continue;
  			/*
  			 * Record the control region for the dimm.  For
  			 * the ACPI 6.1 case, where there are separate
  			 * control regions for the pmem vs blk
  			 * interfaces, be sure to record the extended
  			 * blk details.
  			 */
  			if (!nfit_mem->dcr)
  				nfit_mem->dcr = nfit_dcr->dcr;
  			else if (nfit_mem->dcr->windows == 0
  					&& nfit_dcr->dcr->windows)
  				nfit_mem->dcr = nfit_dcr->dcr;
  			break;
  		}
  
  		if (dcr && !nfit_mem->dcr) {
  			dev_err(acpi_desc->dev, "SPA %d missing DCR %d\n",
  					spa->range_index, dcr);
  			return -ENODEV;
  		}
  
  		if (type == NFIT_SPA_DCR) {
  			struct nfit_idt *nfit_idt;
  			u16 idt_idx;
  
  			/* multiple dimms may share a SPA when interleaved */
  			nfit_mem->spa_dcr = spa;
  			nfit_mem->memdev_dcr = nfit_memdev->memdev;
  			idt_idx = nfit_memdev->memdev->interleave_index;
  			list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
  				if (nfit_idt->idt->interleave_index != idt_idx)
  					continue;
  				nfit_mem->idt_dcr = nfit_idt->idt;
  				break;
  			}
  			nfit_mem_init_bdw(acpi_desc, nfit_mem, spa);
  		} else {
  			/*
  			 * A single dimm may belong to multiple SPA-PM
  			 * ranges, record at least one in addition to
  			 * any SPA-DCR range.
  			 */
  			nfit_mem->memdev_pmem = nfit_memdev->memdev;
  		}
  	}
  
  	return 0;
  }
  
  static int nfit_mem_cmp(void *priv, struct list_head *_a, struct list_head *_b)
  {
  	struct nfit_mem *a = container_of(_a, typeof(*a), list);
  	struct nfit_mem *b = container_of(_b, typeof(*b), list);
  	u32 handleA, handleB;
  
  	handleA = __to_nfit_memdev(a)->device_handle;
  	handleB = __to_nfit_memdev(b)->device_handle;
  	if (handleA < handleB)
  		return -1;
  	else if (handleA > handleB)
  		return 1;
  	return 0;
  }
  
  static int nfit_mem_init(struct acpi_nfit_desc *acpi_desc)
  {
  	struct nfit_spa *nfit_spa;
  
  	/*
  	 * For each SPA-DCR or SPA-PMEM address range find its
  	 * corresponding MEMDEV(s).  From each MEMDEV find the
  	 * corresponding DCR.  Then, if we're operating on a SPA-DCR,
  	 * try to find a SPA-BDW and a corresponding BDW that references
  	 * the DCR.  Throw it all into an nfit_mem object.  Note, that
  	 * BDWs are optional.
  	 */
  	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
  		int rc;
  
  		rc = nfit_mem_dcr_init(acpi_desc, nfit_spa->spa);
  		if (rc)
  			return rc;
  	}
  
  	list_sort(NULL, &acpi_desc->dimms, nfit_mem_cmp);
  
  	return 0;
  }
  
  static ssize_t revision_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
  	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
  	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
  
  	return sprintf(buf, "%d\n", acpi_desc->acpi_header.revision);
  }
  static DEVICE_ATTR_RO(revision);
  
  static struct attribute *acpi_nfit_attributes[] = {
  	&dev_attr_revision.attr,
  	NULL,
  };
  
  static struct attribute_group acpi_nfit_attribute_group = {
  	.name = "nfit",
  	.attrs = acpi_nfit_attributes,
  };
  
  const struct attribute_group *acpi_nfit_attribute_groups[] = {
  	&nvdimm_bus_attribute_group,
  	&acpi_nfit_attribute_group,
  	NULL,
  };
  EXPORT_SYMBOL_GPL(acpi_nfit_attribute_groups);
  
  static struct acpi_nfit_memory_map *to_nfit_memdev(struct device *dev)
  {
  	struct nvdimm *nvdimm = to_nvdimm(dev);
  	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
  
  	return __to_nfit_memdev(nfit_mem);
  }
  
  static struct acpi_nfit_control_region *to_nfit_dcr(struct device *dev)
  {
  	struct nvdimm *nvdimm = to_nvdimm(dev);
  	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
  
  	return nfit_mem->dcr;
  }
  
  static ssize_t handle_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_memory_map *memdev = to_nfit_memdev(dev);
  
  	return sprintf(buf, "%#x\n", memdev->device_handle);
  }
  static DEVICE_ATTR_RO(handle);
  
  static ssize_t phys_id_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_memory_map *memdev = to_nfit_memdev(dev);
  
  	return sprintf(buf, "%#x\n", memdev->physical_id);
  }
  static DEVICE_ATTR_RO(phys_id);
  
  static ssize_t vendor_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
  
  	return sprintf(buf, "%#x\n", dcr->vendor_id);
  }
  static DEVICE_ATTR_RO(vendor);
  
  static ssize_t rev_id_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
  
  	return sprintf(buf, "%#x\n", dcr->revision_id);
  }
  static DEVICE_ATTR_RO(rev_id);
  
  static ssize_t device_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
  
  	return sprintf(buf, "%#x\n", dcr->device_id);
  }
  static DEVICE_ATTR_RO(device);
  
  static ssize_t format_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
  
  	return sprintf(buf, "%#x\n", dcr->code);
  }
  static DEVICE_ATTR_RO(format);
  
  static ssize_t serial_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
  
  	return sprintf(buf, "%#x\n", dcr->serial_number);
  }
  static DEVICE_ATTR_RO(serial);
  
  static ssize_t flags_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	u16 flags = to_nfit_memdev(dev)->flags;
  
  	return sprintf(buf, "%s%s%s%s%s\n",
  		flags & ACPI_NFIT_MEM_SAVE_FAILED ? "save_fail " : "",
  		flags & ACPI_NFIT_MEM_RESTORE_FAILED ? "restore_fail " : "",
  		flags & ACPI_NFIT_MEM_FLUSH_FAILED ? "flush_fail " : "",
  		flags & ACPI_NFIT_MEM_NOT_ARMED ? "not_armed " : "",
  		flags & ACPI_NFIT_MEM_HEALTH_OBSERVED ? "smart_event " : "");
  }
  static DEVICE_ATTR_RO(flags);
  
  static struct attribute *acpi_nfit_dimm_attributes[] = {
  	&dev_attr_handle.attr,
  	&dev_attr_phys_id.attr,
  	&dev_attr_vendor.attr,
  	&dev_attr_device.attr,
  	&dev_attr_format.attr,
  	&dev_attr_serial.attr,
  	&dev_attr_rev_id.attr,
  	&dev_attr_flags.attr,
  	NULL,
  };
  
  static umode_t acpi_nfit_dimm_attr_visible(struct kobject *kobj,
  		struct attribute *a, int n)
  {
  	struct device *dev = container_of(kobj, struct device, kobj);
  
  	if (to_nfit_dcr(dev))
  		return a->mode;
  	else
  		return 0;
  }
  
  static struct attribute_group acpi_nfit_dimm_attribute_group = {
  	.name = "nfit",
  	.attrs = acpi_nfit_dimm_attributes,
  	.is_visible = acpi_nfit_dimm_attr_visible,
  };
  
  static const struct attribute_group *acpi_nfit_dimm_attribute_groups[] = {
  	&nvdimm_attribute_group,
  	&nd_device_attribute_group,
  	&acpi_nfit_dimm_attribute_group,
  	NULL,
  };
  
  static struct nvdimm *acpi_nfit_dimm_by_handle(struct acpi_nfit_desc *acpi_desc,
  		u32 device_handle)
  {
  	struct nfit_mem *nfit_mem;
  
  	list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
  		if (__to_nfit_memdev(nfit_mem)->device_handle == device_handle)
  			return nfit_mem->nvdimm;
  
  	return NULL;
  }
  
  static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_mem *nfit_mem, u32 device_handle)
  {
  	struct acpi_device *adev, *adev_dimm;
  	struct device *dev = acpi_desc->dev;
  	const u8 *uuid = to_nfit_uuid(NFIT_DEV_DIMM);
  	int i;
  
  	nfit_mem->dsm_mask = acpi_desc->dimm_dsm_force_en;
  	adev = to_acpi_dev(acpi_desc);
  	if (!adev)
  		return 0;
  
  	adev_dimm = acpi_find_child_device(adev, device_handle, false);
  	nfit_mem->adev = adev_dimm;
  	if (!adev_dimm) {
  		dev_err(dev, "no ACPI.NFIT device with _ADR %#x, disabling...\n",
  				device_handle);
  		return force_enable_dimms ? 0 : -ENODEV;
  	}
  
  	for (i = ND_CMD_SMART; i <= ND_CMD_VENDOR; i++)
  		if (acpi_check_dsm(adev_dimm->handle, uuid, 1, 1ULL << i))
  			set_bit(i, &nfit_mem->dsm_mask);
  
  	return 0;
  }
  
  static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
  {
  	struct nfit_mem *nfit_mem;
  	int dimm_count = 0;
  
  	list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) {
  		struct nvdimm *nvdimm;
  		unsigned long flags = 0;
  		u32 device_handle;
  		u16 mem_flags;
  		int rc;
  
  		device_handle = __to_nfit_memdev(nfit_mem)->device_handle;
  		nvdimm = acpi_nfit_dimm_by_handle(acpi_desc, device_handle);
  		if (nvdimm) {
  			dimm_count++;
  			continue;
  		}
  
  		if (nfit_mem->bdw && nfit_mem->memdev_pmem)
  			flags |= NDD_ALIASING;
  
  		mem_flags = __to_nfit_memdev(nfit_mem)->flags;
  		if (mem_flags & ACPI_NFIT_MEM_NOT_ARMED)
  			flags |= NDD_UNARMED;
  
  		rc = acpi_nfit_add_dimm(acpi_desc, nfit_mem, device_handle);
  		if (rc)
  			continue;
  
  		nvdimm = nvdimm_create(acpi_desc->nvdimm_bus, nfit_mem,
  				acpi_nfit_dimm_attribute_groups,
  				flags, &nfit_mem->dsm_mask);
  		if (!nvdimm)
  			return -ENOMEM;
  
  		nfit_mem->nvdimm = nvdimm;
  		dimm_count++;
  
  		if ((mem_flags & ACPI_NFIT_MEM_FAILED_MASK) == 0)
  			continue;
  
  		dev_info(acpi_desc->dev, "%s flags:%s%s%s%s\n",
  				nvdimm_name(nvdimm),
  		  mem_flags & ACPI_NFIT_MEM_SAVE_FAILED ? " save_fail" : "",
  		  mem_flags & ACPI_NFIT_MEM_RESTORE_FAILED ? " restore_fail":"",
  		  mem_flags & ACPI_NFIT_MEM_FLUSH_FAILED ? " flush_fail" : "",
  		  mem_flags & ACPI_NFIT_MEM_NOT_ARMED ? " not_armed" : "");
  
  	}
  
  	return nvdimm_bus_check_dimm_count(acpi_desc->nvdimm_bus, dimm_count);
  }
  
  static void acpi_nfit_init_dsms(struct acpi_nfit_desc *acpi_desc)
  {
  	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
  	const u8 *uuid = to_nfit_uuid(NFIT_DEV_BUS);
  	struct acpi_device *adev;
  	int i;
  
  	nd_desc->dsm_mask = acpi_desc->bus_dsm_force_en;
  	adev = to_acpi_dev(acpi_desc);
  	if (!adev)
  		return;
  
  	for (i = ND_CMD_ARS_CAP; i <= ND_CMD_ARS_STATUS; i++)
  		if (acpi_check_dsm(adev->handle, uuid, 1, 1ULL << i))
  			set_bit(i, &nd_desc->dsm_mask);
  }
  
  static ssize_t range_index_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct nd_region *nd_region = to_nd_region(dev);
  	struct nfit_spa *nfit_spa = nd_region_provider_data(nd_region);
  
  	return sprintf(buf, "%d\n", nfit_spa->spa->range_index);
  }
  static DEVICE_ATTR_RO(range_index);
  
  static struct attribute *acpi_nfit_region_attributes[] = {
  	&dev_attr_range_index.attr,
  	NULL,
  };
  
  static struct attribute_group acpi_nfit_region_attribute_group = {
  	.name = "nfit",
  	.attrs = acpi_nfit_region_attributes,
  };
  
  static const struct attribute_group *acpi_nfit_region_attribute_groups[] = {
  	&nd_region_attribute_group,
  	&nd_mapping_attribute_group,
  	&nd_device_attribute_group,
  	&nd_numa_attribute_group,
  	&acpi_nfit_region_attribute_group,
  	NULL,
  };
  
  /* enough info to uniquely specify an interleave set */
  struct nfit_set_info {
  	struct nfit_set_info_map {
  		u64 region_offset;
  		u32 serial_number;
  		u32 pad;
  	} mapping[0];
  };
  
  static size_t sizeof_nfit_set_info(int num_mappings)
  {
  	return sizeof(struct nfit_set_info)
  		+ num_mappings * sizeof(struct nfit_set_info_map);
  }
  
  static int cmp_map(const void *m0, const void *m1)
  {
  	const struct nfit_set_info_map *map0 = m0;
  	const struct nfit_set_info_map *map1 = m1;
  
  	return memcmp(&map0->region_offset, &map1->region_offset,
  			sizeof(u64));
  }
  
  /* Retrieve the nth entry referencing this spa */
  static struct acpi_nfit_memory_map *memdev_from_spa(
  		struct acpi_nfit_desc *acpi_desc, u16 range_index, int n)
  {
  	struct nfit_memdev *nfit_memdev;
  
  	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list)
  		if (nfit_memdev->memdev->range_index == range_index)
  			if (n-- == 0)
  				return nfit_memdev->memdev;
  	return NULL;
  }
  
  static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
  		struct nd_region_desc *ndr_desc,
  		struct acpi_nfit_system_address *spa)
  {
  	int i, spa_type = nfit_spa_type(spa);
  	struct device *dev = acpi_desc->dev;
  	struct nd_interleave_set *nd_set;
  	u16 nr = ndr_desc->num_mappings;
  	struct nfit_set_info *info;
  
  	if (spa_type == NFIT_SPA_PM || spa_type == NFIT_SPA_VOLATILE)
  		/* pass */;
  	else
  		return 0;
  
  	nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
  	if (!nd_set)
  		return -ENOMEM;
  
  	info = devm_kzalloc(dev, sizeof_nfit_set_info(nr), GFP_KERNEL);
  	if (!info)
  		return -ENOMEM;
  	for (i = 0; i < nr; i++) {
  		struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
  		struct nfit_set_info_map *map = &info->mapping[i];
  		struct nvdimm *nvdimm = nd_mapping->nvdimm;
  		struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
  		struct acpi_nfit_memory_map *memdev = memdev_from_spa(acpi_desc,
  				spa->range_index, i);
  
  		if (!memdev || !nfit_mem->dcr) {
  			dev_err(dev, "%s: failed to find DCR\n", __func__);
  			return -ENODEV;
  		}
  
  		map->region_offset = memdev->region_offset;
  		map->serial_number = nfit_mem->dcr->serial_number;
  	}
  
  	sort(&info->mapping[0], nr, sizeof(struct nfit_set_info_map),
  			cmp_map, NULL);
  	nd_set->cookie = nd_fletcher64(info, sizeof_nfit_set_info(nr), 0);
  	ndr_desc->nd_set = nd_set;
  	devm_kfree(dev, info);
  
  	return 0;
  }
  
  static u64 to_interleave_offset(u64 offset, struct nfit_blk_mmio *mmio)
  {
  	struct acpi_nfit_interleave *idt = mmio->idt;
  	u32 sub_line_offset, line_index, line_offset;
  	u64 line_no, table_skip_count, table_offset;
  
  	line_no = div_u64_rem(offset, mmio->line_size, &sub_line_offset);
  	table_skip_count = div_u64_rem(line_no, mmio->num_lines, &line_index);
  	line_offset = idt->line_offset[line_index]
  		* mmio->line_size;
  	table_offset = table_skip_count * mmio->table_size;
  
  	return mmio->base_offset + line_offset + table_offset + sub_line_offset;
  }
  
  static void wmb_blk(struct nfit_blk *nfit_blk)
  {
  
  	if (nfit_blk->nvdimm_flush) {
  		/*
  		 * The first wmb() is needed to 'sfence' all previous writes
  		 * such that they are architecturally visible for the platform
  		 * buffer flush.  Note that we've already arranged for pmem
  		 * writes to avoid the cache via arch_memcpy_to_pmem().  The
  		 * final wmb() ensures ordering for the NVDIMM flush write.
  		 */
  		wmb();
  		writeq(1, nfit_blk->nvdimm_flush);
  		wmb();
  	} else
  		wmb_pmem();
  }
  
  static u32 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
  {
  	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
  	u64 offset = nfit_blk->stat_offset + mmio->size * bw;
  
  	if (mmio->num_lines)
  		offset = to_interleave_offset(offset, mmio);
  
  	return readl(mmio->addr.base + offset);
  }
  
  static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,
  		resource_size_t dpa, unsigned int len, unsigned int write)
  {
  	u64 cmd, offset;
  	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
  
  	enum {
  		BCW_OFFSET_MASK = (1ULL << 48)-1,
  		BCW_LEN_SHIFT = 48,
  		BCW_LEN_MASK = (1ULL << 8) - 1,
  		BCW_CMD_SHIFT = 56,
  	};
  
  	cmd = (dpa >> L1_CACHE_SHIFT) & BCW_OFFSET_MASK;
  	len = len >> L1_CACHE_SHIFT;
  	cmd |= ((u64) len & BCW_LEN_MASK) << BCW_LEN_SHIFT;
  	cmd |= ((u64) write) << BCW_CMD_SHIFT;
  
  	offset = nfit_blk->cmd_offset + mmio->size * bw;
  	if (mmio->num_lines)
  		offset = to_interleave_offset(offset, mmio);
  
  	writeq(cmd, mmio->addr.base + offset);
  	wmb_blk(nfit_blk);
  
  	if (nfit_blk->dimm_flags & ND_BLK_DCR_LATCH)
  		readq(mmio->addr.base + offset);
  }
  
  static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk,
  		resource_size_t dpa, void *iobuf, size_t len, int rw,
  		unsigned int lane)
  {
  	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
  	unsigned int copied = 0;
  	u64 base_offset;
  	int rc;
  
  	base_offset = nfit_blk->bdw_offset + dpa % L1_CACHE_BYTES
  		+ lane * mmio->size;
  	write_blk_ctl(nfit_blk, lane, dpa, len, rw);
  	while (len) {
  		unsigned int c;
  		u64 offset;
  
  		if (mmio->num_lines) {
  			u32 line_offset;
  
  			offset = to_interleave_offset(base_offset + copied,
  					mmio);
  			div_u64_rem(offset, mmio->line_size, &line_offset);
  			c = min_t(size_t, len, mmio->line_size - line_offset);
  		} else {
  			offset = base_offset + nfit_blk->bdw_offset;
  			c = len;
  		}
  
  		if (rw)
  			memcpy_to_pmem(mmio->addr.aperture + offset,
  					iobuf + copied, c);
  		else {
  			if (nfit_blk->dimm_flags & ND_BLK_READ_FLUSH)
  				mmio_flush_range((void __force *)
  					mmio->addr.aperture + offset, c);
  
  			memcpy_from_pmem(iobuf + copied,
  					mmio->addr.aperture + offset, c);
  		}
  
  		copied += c;
  		len -= c;
  	}
  
  	if (rw)
  		wmb_blk(nfit_blk);
  
  	rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
  	return rc;
  }
  
  static int acpi_nfit_blk_region_do_io(struct nd_blk_region *ndbr,
  		resource_size_t dpa, void *iobuf, u64 len, int rw)
  {
  	struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
  	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
  	struct nd_region *nd_region = nfit_blk->nd_region;
  	unsigned int lane, copied = 0;
  	int rc = 0;
  
  	lane = nd_region_acquire_lane(nd_region);
  	while (len) {
  		u64 c = min(len, mmio->size);
  
  		rc = acpi_nfit_blk_single_io(nfit_blk, dpa + copied,
  				iobuf + copied, c, rw, lane);
  		if (rc)
  			break;
  
  		copied += c;
  		len -= c;
  	}
  	nd_region_release_lane(nd_region, lane);
  
  	return rc;
  }
  
  static void nfit_spa_mapping_release(struct kref *kref)
  {
  	struct nfit_spa_mapping *spa_map = to_spa_map(kref);
  	struct acpi_nfit_system_address *spa = spa_map->spa;
  	struct acpi_nfit_desc *acpi_desc = spa_map->acpi_desc;
  
  	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
  	dev_dbg(acpi_desc->dev, "%s: SPA%d\n", __func__, spa->range_index);
  	if (spa_map->type == SPA_MAP_APERTURE)
  		memunmap((void __force *)spa_map->addr.aperture);
  	else
  		iounmap(spa_map->addr.base);
  	release_mem_region(spa->address, spa->length);
  	list_del(&spa_map->list);
  	kfree(spa_map);
  }
  
  static struct nfit_spa_mapping *find_spa_mapping(
  		struct acpi_nfit_desc *acpi_desc,
  		struct acpi_nfit_system_address *spa)
  {
  	struct nfit_spa_mapping *spa_map;
  
  	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
  	list_for_each_entry(spa_map, &acpi_desc->spa_maps, list)
  		if (spa_map->spa == spa)
  			return spa_map;
  
  	return NULL;
  }
  
  static void nfit_spa_unmap(struct acpi_nfit_desc *acpi_desc,
  		struct acpi_nfit_system_address *spa)
  {
  	struct nfit_spa_mapping *spa_map;
  
  	mutex_lock(&acpi_desc->spa_map_mutex);
  	spa_map = find_spa_mapping(acpi_desc, spa);
  
  	if (spa_map)
  		kref_put(&spa_map->kref, nfit_spa_mapping_release);
  	mutex_unlock(&acpi_desc->spa_map_mutex);
  }
  
  static void __iomem *__nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
  		struct acpi_nfit_system_address *spa, enum spa_map_type type)
  {
  	resource_size_t start = spa->address;
  	resource_size_t n = spa->length;
  	struct nfit_spa_mapping *spa_map;
  	struct resource *res;
  
  	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
  
  	spa_map = find_spa_mapping(acpi_desc, spa);
  	if (spa_map) {
  		kref_get(&spa_map->kref);
  		return spa_map->addr.base;
  	}
  
  	spa_map = kzalloc(sizeof(*spa_map), GFP_KERNEL);
  	if (!spa_map)
  		return NULL;
  
  	INIT_LIST_HEAD(&spa_map->list);
  	spa_map->spa = spa;
  	kref_init(&spa_map->kref);
  	spa_map->acpi_desc = acpi_desc;
  
  	res = request_mem_region(start, n, dev_name(acpi_desc->dev));
  	if (!res)
  		goto err_mem;
  
  	spa_map->type = type;
  	if (type == SPA_MAP_APERTURE)
  		spa_map->addr.aperture = (void __pmem *)memremap(start, n,
  							ARCH_MEMREMAP_PMEM);
  	else
  		spa_map->addr.base = ioremap_nocache(start, n);
  
  
  	if (!spa_map->addr.base)
  		goto err_map;
  
  	list_add_tail(&spa_map->list, &acpi_desc->spa_maps);
  	return spa_map->addr.base;
  
   err_map:
  	release_mem_region(start, n);
   err_mem:
  	kfree(spa_map);
  	return NULL;
  }
  
  /**
   * nfit_spa_map - interleave-aware managed-mappings of acpi_nfit_system_address ranges
   * @nvdimm_bus: NFIT-bus that provided the spa table entry
   * @nfit_spa: spa table to map
   * @type: aperture or control region
   *
   * In the case where block-data-window apertures and
   * dimm-control-regions are interleaved they will end up sharing a
   * single request_mem_region() + ioremap() for the address range.  In
   * the style of devm nfit_spa_map() mappings are automatically dropped
   * when all region devices referencing the same mapping are disabled /
   * unbound.
   */
  static void __iomem *nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
  		struct acpi_nfit_system_address *spa, enum spa_map_type type)
  {
  	void __iomem *iomem;
  
  	mutex_lock(&acpi_desc->spa_map_mutex);
  	iomem = __nfit_spa_map(acpi_desc, spa, type);
  	mutex_unlock(&acpi_desc->spa_map_mutex);
  
  	return iomem;
  }
  
  static int nfit_blk_init_interleave(struct nfit_blk_mmio *mmio,
  		struct acpi_nfit_interleave *idt, u16 interleave_ways)
  {
  	if (idt) {
  		mmio->num_lines = idt->line_count;
  		mmio->line_size = idt->line_size;
  		if (interleave_ways == 0)
  			return -ENXIO;
  		mmio->table_size = mmio->num_lines * interleave_ways
  			* mmio->line_size;
  	}
  
  	return 0;
  }
  
  static int acpi_nfit_blk_get_flags(struct nvdimm_bus_descriptor *nd_desc,
  		struct nvdimm *nvdimm, struct nfit_blk *nfit_blk)
  {
  	struct nd_cmd_dimm_flags flags;
  	int rc;
  
  	memset(&flags, 0, sizeof(flags));
  	rc = nd_desc->ndctl(nd_desc, nvdimm, ND_CMD_DIMM_FLAGS, &flags,
  			sizeof(flags));
  
  	if (rc >= 0 && flags.status == 0)
  		nfit_blk->dimm_flags = flags.flags;
  	else if (rc == -ENOTTY) {
  		/* fall back to a conservative default */
  		nfit_blk->dimm_flags = ND_BLK_DCR_LATCH | ND_BLK_READ_FLUSH;
  		rc = 0;
  	} else
  		rc = -ENXIO;
  
  	return rc;
  }
  
  static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
  		struct device *dev)
  {
  	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
  	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
  	struct nd_blk_region *ndbr = to_nd_blk_region(dev);
  	struct nfit_flush *nfit_flush;
  	struct nfit_blk_mmio *mmio;
  	struct nfit_blk *nfit_blk;
  	struct nfit_mem *nfit_mem;
  	struct nvdimm *nvdimm;
  	int rc;
  
  	nvdimm = nd_blk_region_to_dimm(ndbr);
  	nfit_mem = nvdimm_provider_data(nvdimm);
  	if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
  		dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
  				nfit_mem ? "" : " nfit_mem",
  				(nfit_mem && nfit_mem->dcr) ? "" : " dcr",
  				(nfit_mem && nfit_mem->bdw) ? "" : " bdw");
  		return -ENXIO;
  	}
  
  	nfit_blk = devm_kzalloc(dev, sizeof(*nfit_blk), GFP_KERNEL);
  	if (!nfit_blk)
  		return -ENOMEM;
  	nd_blk_region_set_provider_data(ndbr, nfit_blk);
  	nfit_blk->nd_region = to_nd_region(dev);
  
  	/* map block aperture memory */
  	nfit_blk->bdw_offset = nfit_mem->bdw->offset;
  	mmio = &nfit_blk->mmio[BDW];
  	mmio->addr.base = nfit_spa_map(acpi_desc, nfit_mem->spa_bdw,
  			SPA_MAP_APERTURE);
  	if (!mmio->addr.base) {
  		dev_dbg(dev, "%s: %s failed to map bdw\n", __func__,
  				nvdimm_name(nvdimm));
  		return -ENOMEM;
  	}
  	mmio->size = nfit_mem->bdw->size;
  	mmio->base_offset = nfit_mem->memdev_bdw->region_offset;
  	mmio->idt = nfit_mem->idt_bdw;
  	mmio->spa = nfit_mem->spa_bdw;
  	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_bdw,
  			nfit_mem->memdev_bdw->interleave_ways);
  	if (rc) {
  		dev_dbg(dev, "%s: %s failed to init bdw interleave\n",
  				__func__, nvdimm_name(nvdimm));
  		return rc;
  	}
  
  	/* map block control memory */
  	nfit_blk->cmd_offset = nfit_mem->dcr->command_offset;
  	nfit_blk->stat_offset = nfit_mem->dcr->status_offset;
  	mmio = &nfit_blk->mmio[DCR];
  	mmio->addr.base = nfit_spa_map(acpi_desc, nfit_mem->spa_dcr,
  			SPA_MAP_CONTROL);
  	if (!mmio->addr.base) {
  		dev_dbg(dev, "%s: %s failed to map dcr\n", __func__,
  				nvdimm_name(nvdimm));
  		return -ENOMEM;
  	}
  	mmio->size = nfit_mem->dcr->window_size;
  	mmio->base_offset = nfit_mem->memdev_dcr->region_offset;
  	mmio->idt = nfit_mem->idt_dcr;
  	mmio->spa = nfit_mem->spa_dcr;
  	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_dcr,
  			nfit_mem->memdev_dcr->interleave_ways);
  	if (rc) {
  		dev_dbg(dev, "%s: %s failed to init dcr interleave\n",
  				__func__, nvdimm_name(nvdimm));
  		return rc;
  	}
  
  	rc = acpi_nfit_blk_get_flags(nd_desc, nvdimm, nfit_blk);
  	if (rc < 0) {
  		dev_dbg(dev, "%s: %s failed get DIMM flags\n",
  				__func__, nvdimm_name(nvdimm));
  		return rc;
  	}
  
  	nfit_flush = nfit_mem->nfit_flush;
  	if (nfit_flush && nfit_flush->flush->hint_count != 0) {
  		nfit_blk->nvdimm_flush = devm_ioremap_nocache(dev,
  				nfit_flush->flush->hint_address[0], 8);
  		if (!nfit_blk->nvdimm_flush)
  			return -ENOMEM;
  	}
  
  	if (!arch_has_wmb_pmem() && !nfit_blk->nvdimm_flush)
  		dev_warn(dev, "unable to guarantee persistence of writes\n");
  
  	if (mmio->line_size == 0)
  		return 0;
  
  	if ((u32) nfit_blk->cmd_offset % mmio->line_size
  			+ 8 > mmio->line_size) {
  		dev_dbg(dev, "cmd_offset crosses interleave boundary\n");
  		return -ENXIO;
  	} else if ((u32) nfit_blk->stat_offset % mmio->line_size
  			+ 8 > mmio->line_size) {
  		dev_dbg(dev, "stat_offset crosses interleave boundary\n");
  		return -ENXIO;
  	}
  
  	return 0;
  }
  
  static void acpi_nfit_blk_region_disable(struct nvdimm_bus *nvdimm_bus,
  		struct device *dev)
  {
  	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
  	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
  	struct nd_blk_region *ndbr = to_nd_blk_region(dev);
  	struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
  	int i;
  
  	if (!nfit_blk)
  		return; /* never enabled */
  
  	/* auto-free BLK spa mappings */
  	for (i = 0; i < 2; i++) {
  		struct nfit_blk_mmio *mmio = &nfit_blk->mmio[i];
  
  		if (mmio->addr.base)
  			nfit_spa_unmap(acpi_desc, mmio->spa);
  	}
  	nd_blk_region_set_provider_data(ndbr, NULL);
  	/* devm will free nfit_blk */
  }
  
  static int ars_get_cap(struct nvdimm_bus_descriptor *nd_desc,
  		struct nd_cmd_ars_cap *cmd, u64 addr, u64 length)
  {
  	cmd->address = addr;
  	cmd->length = length;
  
  	return nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, cmd,
  			sizeof(*cmd));
  }
  
  static int ars_do_start(struct nvdimm_bus_descriptor *nd_desc,
  		struct nd_cmd_ars_start *cmd, u64 addr, u64 length)
  {
  	int rc;
  
  	cmd->address = addr;
  	cmd->length = length;
  	cmd->type = ND_ARS_PERSISTENT;
  
  	while (1) {
  		rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, cmd,
  				sizeof(*cmd));
  		if (rc)
  			return rc;
  		switch (cmd->status) {
  		case 0:
  			return 0;
  		case 1:
  			/* ARS unsupported, but we should never get here */
  			return 0;
  		case 6:
  			/* ARS is in progress */
  			msleep(1000);
  			break;
  		default:
  			return -ENXIO;
  		}
  	}
  }
  
  static int ars_get_status(struct nvdimm_bus_descriptor *nd_desc,
  		struct nd_cmd_ars_status *cmd, u32 size)
  {
  	int rc;
  
  	while (1) {
  		rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, cmd,
  			size);
  		if (rc || cmd->status & 0xffff)
  			return -ENXIO;
  
  		/* Check extended status (Upper two bytes) */
  		switch (cmd->status >> 16) {
  		case 0:
  			return 0;
  		case 1:
  			/* ARS is in progress */
  			msleep(1000);
  			break;
  		case 2:
  			/* No ARS performed for the current boot */
  			return 0;
  		case 3:
  			/* TODO: error list overflow support */
  		default:
  			return -ENXIO;
  		}
  	}
  }
  
  static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
  		struct nd_cmd_ars_status *ars_status, u64 start)
  {
  	int rc;
  	u32 i;
  
  	/*
  	 * The address field returned by ars_status should be either
  	 * less than or equal to the address we last started ARS for.
  	 * The (start, length) returned by ars_status should also have
  	 * non-zero overlap with the range we started ARS for.
  	 * If this is not the case, bail.
  	 */
  	if (ars_status->address > start ||
  			(ars_status->address + ars_status->length < start))
  		return -ENXIO;
  
  	for (i = 0; i < ars_status->num_records; i++) {
  		rc = nvdimm_bus_add_poison(nvdimm_bus,
  				ars_status->records[i].err_address,
  				ars_status->records[i].length);
  		if (rc)
  			return rc;
  	}
  
  	return 0;
  }
  
  static int acpi_nfit_find_poison(struct acpi_nfit_desc *acpi_desc,
  		struct nd_region_desc *ndr_desc)
  {
  	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
  	struct nvdimm_bus *nvdimm_bus = acpi_desc->nvdimm_bus;
  	struct nd_cmd_ars_status *ars_status = NULL;
  	struct nd_cmd_ars_start *ars_start = NULL;
  	struct nd_cmd_ars_cap *ars_cap = NULL;
  	u64 start, len, cur, remaining;
  	u32 ars_status_size;
  	int rc;
  
  	ars_cap = kzalloc(sizeof(*ars_cap), GFP_KERNEL);
  	if (!ars_cap)
  		return -ENOMEM;
  
  	start = ndr_desc->res->start;
  	len = ndr_desc->res->end - ndr_desc->res->start + 1;
  
  	/*
  	 * If ARS is unimplemented, unsupported, or if the 'Persistent Memory
  	 * Scrub' flag in extended status is not set, skip this but continue
  	 * initialization
  	 */
  	rc = ars_get_cap(nd_desc, ars_cap, start, len);
  	if (rc == -ENOTTY) {
  		dev_dbg(acpi_desc->dev,
  			"Address Range Scrub is not implemented, won't create an error list\n");
  		rc = 0;
  		goto out;
  	}
  	if (rc)
  		goto out;
  
  	if ((ars_cap->status & 0xffff) ||
  		!(ars_cap->status >> 16 & ND_ARS_PERSISTENT)) {
  		dev_warn(acpi_desc->dev,
  			"ARS unsupported (status: 0x%x), won't create an error list\n",
  			ars_cap->status);
  		goto out;
  	}
  
  	/*
  	 * Check if a full-range ARS has been run. If so, use those results
  	 * without having to start a new ARS.
  	 */
  	ars_status_size = ars_cap->max_ars_out;
  	ars_status = kzalloc(ars_status_size, GFP_KERNEL);
  	if (!ars_status) {
  		rc = -ENOMEM;
  		goto out;
  	}
  
  	rc = ars_get_status(nd_desc, ars_status, ars_status_size);
  	if (rc)
  		goto out;
  
  	if (ars_status->address <= start &&
  		(ars_status->address + ars_status->length >= start + len)) {
  		rc = ars_status_process_records(nvdimm_bus, ars_status, start);
  		goto out;
  	}
  
  	/*
  	 * ARS_STATUS can overflow if the number of poison entries found is
  	 * greater than the maximum buffer size (ars_cap->max_ars_out)
  	 * To detect overflow, check if the length field of ars_status
  	 * is less than the length we supplied. If so, process the
  	 * error entries we got, adjust the start point, and start again
  	 */
  	ars_start = kzalloc(sizeof(*ars_start), GFP_KERNEL);
  	if (!ars_start)
  		return -ENOMEM;
  
  	cur = start;
  	remaining = len;
  	do {
  		u64 done, end;
  
  		rc = ars_do_start(nd_desc, ars_start, cur, remaining);
  		if (rc)
  			goto out;
  
  		rc = ars_get_status(nd_desc, ars_status, ars_status_size);
  		if (rc)
  			goto out;
  
  		rc = ars_status_process_records(nvdimm_bus, ars_status, cur);
  		if (rc)
  			goto out;
  
  		end = min(cur + remaining,
  			ars_status->address + ars_status->length);
  		done = end - cur;
  		cur += done;
  		remaining -= done;
  	} while (remaining);
  
   out:
  	kfree(ars_cap);
  	kfree(ars_start);
  	kfree(ars_status);
  	return rc;
  }
  
  static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
  		struct nd_mapping *nd_mapping, struct nd_region_desc *ndr_desc,
  		struct acpi_nfit_memory_map *memdev,
  		struct acpi_nfit_system_address *spa)
  {
  	struct nvdimm *nvdimm = acpi_nfit_dimm_by_handle(acpi_desc,
  			memdev->device_handle);
  	struct nd_blk_region_desc *ndbr_desc;
  	struct nfit_mem *nfit_mem;
  	int blk_valid = 0;
  
  	if (!nvdimm) {
  		dev_err(acpi_desc->dev, "spa%d dimm: %#x not found\n",
  				spa->range_index, memdev->device_handle);
  		return -ENODEV;
  	}
  
  	nd_mapping->nvdimm = nvdimm;
  	switch (nfit_spa_type(spa)) {
  	case NFIT_SPA_PM:
  	case NFIT_SPA_VOLATILE:
  		nd_mapping->start = memdev->address;
  		nd_mapping->size = memdev->region_size;
  		break;
  	case NFIT_SPA_DCR:
  		nfit_mem = nvdimm_provider_data(nvdimm);
  		if (!nfit_mem || !nfit_mem->bdw) {
  			dev_dbg(acpi_desc->dev, "spa%d %s missing bdw\n",
  					spa->range_index, nvdimm_name(nvdimm));
  		} else {
  			nd_mapping->size = nfit_mem->bdw->capacity;
  			nd_mapping->start = nfit_mem->bdw->start_address;
  			ndr_desc->num_lanes = nfit_mem->bdw->windows;
  			blk_valid = 1;
  		}
  
  		ndr_desc->nd_mapping = nd_mapping;
  		ndr_desc->num_mappings = blk_valid;
  		ndbr_desc = to_blk_region_desc(ndr_desc);
  		ndbr_desc->enable = acpi_nfit_blk_region_enable;
  		ndbr_desc->disable = acpi_nfit_blk_region_disable;
  		ndbr_desc->do_io = acpi_desc->blk_do_io;
  		if (!nvdimm_blk_region_create(acpi_desc->nvdimm_bus, ndr_desc))
  			return -ENOMEM;
  		break;
  	}
  
  	return 0;
  }
  
  static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_spa *nfit_spa)
  {
  	static struct nd_mapping nd_mappings[ND_MAX_MAPPINGS];
  	struct acpi_nfit_system_address *spa = nfit_spa->spa;
  	struct nd_blk_region_desc ndbr_desc;
  	struct nd_region_desc *ndr_desc;
  	struct nfit_memdev *nfit_memdev;
  	struct nvdimm_bus *nvdimm_bus;
  	struct resource res;
  	int count = 0, rc;
  
  	if (nfit_spa->is_registered)
  		return 0;
  
  	if (spa->range_index == 0) {
  		dev_dbg(acpi_desc->dev, "%s: detected invalid spa index\n",
  				__func__);
  		return 0;
  	}
  
  	memset(&res, 0, sizeof(res));
  	memset(&nd_mappings, 0, sizeof(nd_mappings));
  	memset(&ndbr_desc, 0, sizeof(ndbr_desc));
  	res.start = spa->address;
  	res.end = res.start + spa->length - 1;
  	ndr_desc = &ndbr_desc.ndr_desc;
  	ndr_desc->res = &res;
  	ndr_desc->provider_data = nfit_spa;
  	ndr_desc->attr_groups = acpi_nfit_region_attribute_groups;
  	if (spa->flags & ACPI_NFIT_PROXIMITY_VALID)
  		ndr_desc->numa_node = acpi_map_pxm_to_online_node(
  						spa->proximity_domain);
  	else
  		ndr_desc->numa_node = NUMA_NO_NODE;
  
  	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
  		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
  		struct nd_mapping *nd_mapping;
  
  		if (memdev->range_index != spa->range_index)
  			continue;
  		if (count >= ND_MAX_MAPPINGS) {
  			dev_err(acpi_desc->dev, "spa%d exceeds max mappings %d\n",
  					spa->range_index, ND_MAX_MAPPINGS);
  			return -ENXIO;
  		}
  		nd_mapping = &nd_mappings[count++];
  		rc = acpi_nfit_init_mapping(acpi_desc, nd_mapping, ndr_desc,
  				memdev, spa);
  		if (rc)
  			return rc;
  	}
  
  	ndr_desc->nd_mapping = nd_mappings;
  	ndr_desc->num_mappings = count;
  	rc = acpi_nfit_init_interleave_set(acpi_desc, ndr_desc, spa);
  	if (rc)
  		return rc;
  
  	nvdimm_bus = acpi_desc->nvdimm_bus;
  	if (nfit_spa_type(spa) == NFIT_SPA_PM) {
  		rc = acpi_nfit_find_poison(acpi_desc, ndr_desc);
  		if (rc) {
  			dev_err(acpi_desc->dev,
  				"error while performing ARS to find poison: %d\n",
  				rc);
  			return rc;
  		}
  		if (!nvdimm_pmem_region_create(nvdimm_bus, ndr_desc))
  			return -ENOMEM;
  	} else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE) {
  		if (!nvdimm_volatile_region_create(nvdimm_bus, ndr_desc))
  			return -ENOMEM;
  	}
  
  	nfit_spa->is_registered = 1;
  	return 0;
  }
  
  static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
  {
  	struct nfit_spa *nfit_spa;
  
  	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
  		int rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
  
  		if (rc)
  			return rc;
  	}
  	return 0;
  }
  
  static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
  		struct nfit_table_prev *prev)
  {
  	struct device *dev = acpi_desc->dev;
  
  	if (!list_empty(&prev->spas) ||
  			!list_empty(&prev->memdevs) ||
  			!list_empty(&prev->dcrs) ||
  			!list_empty(&prev->bdws) ||
  			!list_empty(&prev->idts) ||
  			!list_empty(&prev->flushes)) {
  		dev_err(dev, "new nfit deletes entries (unsupported)\n");
  		return -ENXIO;
  	}
  	return 0;
  }
  
  int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
  {
  	struct device *dev = acpi_desc->dev;
  	struct nfit_table_prev prev;
  	const void *end;
  	u8 *data;
  	int rc;
  
  	mutex_lock(&acpi_desc->init_mutex);
  
  	INIT_LIST_HEAD(&prev.spas);
  	INIT_LIST_HEAD(&prev.memdevs);
  	INIT_LIST_HEAD(&prev.dcrs);
  	INIT_LIST_HEAD(&prev.bdws);
  	INIT_LIST_HEAD(&prev.idts);
  	INIT_LIST_HEAD(&prev.flushes);
  
  	list_cut_position(&prev.spas, &acpi_desc->spas,
  				acpi_desc->spas.prev);
  	list_cut_position(&prev.memdevs, &acpi_desc->memdevs,
  				acpi_desc->memdevs.prev);
  	list_cut_position(&prev.dcrs, &acpi_desc->dcrs,
  				acpi_desc->dcrs.prev);
  	list_cut_position(&prev.bdws, &acpi_desc->bdws,
  				acpi_desc->bdws.prev);
  	list_cut_position(&prev.idts, &acpi_desc->idts,
  				acpi_desc->idts.prev);
  	list_cut_position(&prev.flushes, &acpi_desc->flushes,
  				acpi_desc->flushes.prev);
  
  	data = (u8 *) acpi_desc->nfit;
  	end = data + sz;
  	while (!IS_ERR_OR_NULL(data))
  		data = add_table(acpi_desc, &prev, data, end);
  
  	if (IS_ERR(data)) {
  		dev_dbg(dev, "%s: nfit table parsing error: %ld\n", __func__,
  				PTR_ERR(data));
  		rc = PTR_ERR(data);
  		goto out_unlock;
  	}
  
  	rc = acpi_nfit_check_deletions(acpi_desc, &prev);
  	if (rc)
  		goto out_unlock;
  
  	if (nfit_mem_init(acpi_desc) != 0) {
  		rc = -ENOMEM;
  		goto out_unlock;
  	}
  
  	acpi_nfit_init_dsms(acpi_desc);
  
  	rc = acpi_nfit_register_dimms(acpi_desc);
  	if (rc)
  		goto out_unlock;
  
  	rc = acpi_nfit_register_regions(acpi_desc);
  
   out_unlock:
  	mutex_unlock(&acpi_desc->init_mutex);
  	return rc;
  }
  EXPORT_SYMBOL_GPL(acpi_nfit_init);
  
  static struct acpi_nfit_desc *acpi_nfit_desc_init(struct acpi_device *adev)
  {
  	struct nvdimm_bus_descriptor *nd_desc;
  	struct acpi_nfit_desc *acpi_desc;
  	struct device *dev = &adev->dev;
  
  	acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
  	if (!acpi_desc)
  		return ERR_PTR(-ENOMEM);
  
  	dev_set_drvdata(dev, acpi_desc);
  	acpi_desc->dev = dev;
  	acpi_desc->blk_do_io = acpi_nfit_blk_region_do_io;
  	nd_desc = &acpi_desc->nd_desc;
  	nd_desc->provider_name = "ACPI.NFIT";
  	nd_desc->ndctl = acpi_nfit_ctl;
  	nd_desc->attr_groups = acpi_nfit_attribute_groups;
  
  	acpi_desc->nvdimm_bus = nvdimm_bus_register(dev, nd_desc);
  	if (!acpi_desc->nvdimm_bus) {
  		devm_kfree(dev, acpi_desc);
  		return ERR_PTR(-ENXIO);
  	}
  
  	INIT_LIST_HEAD(&acpi_desc->spa_maps);
  	INIT_LIST_HEAD(&acpi_desc->spas);
  	INIT_LIST_HEAD(&acpi_desc->dcrs);
  	INIT_LIST_HEAD(&acpi_desc->bdws);
  	INIT_LIST_HEAD(&acpi_desc->idts);
  	INIT_LIST_HEAD(&acpi_desc->flushes);
  	INIT_LIST_HEAD(&acpi_desc->memdevs);
  	INIT_LIST_HEAD(&acpi_desc->dimms);
  	mutex_init(&acpi_desc->spa_map_mutex);
  	mutex_init(&acpi_desc->init_mutex);
  
  	return acpi_desc;
  }
  
  static int acpi_nfit_add(struct acpi_device *adev)
  {
  	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
  	struct acpi_nfit_desc *acpi_desc;
  	struct device *dev = &adev->dev;
  	struct acpi_table_header *tbl;
  	acpi_status status = AE_OK;
  	acpi_size sz;
  	int rc;
  
  	status = acpi_get_table_with_size("NFIT", 0, &tbl, &sz);
  	if (ACPI_FAILURE(status)) {
  		/* This is ok, we could have an nvdimm hotplugged later */
  		dev_dbg(dev, "failed to find NFIT at startup\n");
  		return 0;
  	}
  
  	acpi_desc = acpi_nfit_desc_init(adev);
  	if (IS_ERR(acpi_desc)) {
  		dev_err(dev, "%s: error initializing acpi_desc: %ld\n",
  				__func__, PTR_ERR(acpi_desc));
  		return PTR_ERR(acpi_desc);
  	}
  
  	/*
  	 * Save the acpi header for later and then skip it,
  	 * making nfit point to the first nfit table header.
  	 */
  	acpi_desc->acpi_header = *tbl;
  	acpi_desc->nfit = (void *) tbl + sizeof(struct acpi_table_nfit);
  	sz -= sizeof(struct acpi_table_nfit);
  
  	/* Evaluate _FIT and override with that if present */
  	status = acpi_evaluate_object(adev->handle, "_FIT", NULL, &buf);
  	if (ACPI_SUCCESS(status) && buf.length > 0) {
  		union acpi_object *obj;
  		/*
  		 * Adjust for the acpi_object header of the _FIT
  		 */
  		obj = buf.pointer;
  		if (obj->type == ACPI_TYPE_BUFFER) {
  			acpi_desc->nfit =
  				(struct acpi_nfit_header *)obj->buffer.pointer;
  			sz = obj->buffer.length;
  		} else
  			dev_dbg(dev, "%s invalid type %d, ignoring _FIT\n",
  				 __func__, (int) obj->type);
  	}
  
  	rc = acpi_nfit_init(acpi_desc, sz);
  	if (rc) {
  		nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
  		return rc;
  	}
  	return 0;
  }
  
  static int acpi_nfit_remove(struct acpi_device *adev)
  {
  	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
  
  	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
  	return 0;
  }
  
  static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
  {
  	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
  	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
  	struct acpi_nfit_header *nfit_saved;
  	union acpi_object *obj;
  	struct device *dev = &adev->dev;
  	acpi_status status;
  	int ret;
  
  	dev_dbg(dev, "%s: event: %d\n", __func__, event);
  
  	device_lock(dev);
  	if (!dev->driver) {
  		/* dev->driver may be null if we're being removed */
  		dev_dbg(dev, "%s: no driver found for dev\n", __func__);
  		goto out_unlock;
  	}
  
  	if (!acpi_desc) {
  		acpi_desc = acpi_nfit_desc_init(adev);
  		if (IS_ERR(acpi_desc)) {
  			dev_err(dev, "%s: error initializing acpi_desc: %ld\n",
  				__func__, PTR_ERR(acpi_desc));
  			goto out_unlock;
  		}
  	}
  
  	/* Evaluate _FIT */
  	status = acpi_evaluate_object(adev->handle, "_FIT", NULL, &buf);
  	if (ACPI_FAILURE(status)) {
  		dev_err(dev, "failed to evaluate _FIT\n");
  		goto out_unlock;
  	}
  
  	nfit_saved = acpi_desc->nfit;
  	obj = buf.pointer;
  	if (obj->type == ACPI_TYPE_BUFFER) {
  		acpi_desc->nfit =
  			(struct acpi_nfit_header *)obj->buffer.pointer;
  		ret = acpi_nfit_init(acpi_desc, obj->buffer.length);
  		if (ret) {
  			/* Merge failed, restore old nfit, and exit */
  			acpi_desc->nfit = nfit_saved;
  			dev_err(dev, "failed to merge updated NFIT\n");
  		}
  	} else {
  		/* Bad _FIT, restore old nfit */
  		dev_err(dev, "Invalid _FIT\n");
  	}
  	kfree(buf.pointer);
  
   out_unlock:
  	device_unlock(dev);
  }
  
  static const struct acpi_device_id acpi_nfit_ids[] = {
  	{ "ACPI0012", 0 },
  	{ "", 0 },
  };
  MODULE_DEVICE_TABLE(acpi, acpi_nfit_ids);
  
  static struct acpi_driver acpi_nfit_driver = {
  	.name = KBUILD_MODNAME,
  	.ids = acpi_nfit_ids,
  	.ops = {
  		.add = acpi_nfit_add,
  		.remove = acpi_nfit_remove,
  		.notify = acpi_nfit_notify,
  	},
  };
  
  static __init int nfit_init(void)
  {
  	BUILD_BUG_ON(sizeof(struct acpi_table_nfit) != 40);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_system_address) != 56);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_memory_map) != 48);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_interleave) != 20);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 9);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_control_region) != 80);
  	BUILD_BUG_ON(sizeof(struct acpi_nfit_data_region) != 40);
  
  	acpi_str_to_uuid(UUID_VOLATILE_MEMORY, nfit_uuid[NFIT_SPA_VOLATILE]);
  	acpi_str_to_uuid(UUID_PERSISTENT_MEMORY, nfit_uuid[NFIT_SPA_PM]);
  	acpi_str_to_uuid(UUID_CONTROL_REGION, nfit_uuid[NFIT_SPA_DCR]);
  	acpi_str_to_uuid(UUID_DATA_REGION, nfit_uuid[NFIT_SPA_BDW]);
  	acpi_str_to_uuid(UUID_VOLATILE_VIRTUAL_DISK, nfit_uuid[NFIT_SPA_VDISK]);
  	acpi_str_to_uuid(UUID_VOLATILE_VIRTUAL_CD, nfit_uuid[NFIT_SPA_VCD]);
  	acpi_str_to_uuid(UUID_PERSISTENT_VIRTUAL_DISK, nfit_uuid[NFIT_SPA_PDISK]);
  	acpi_str_to_uuid(UUID_PERSISTENT_VIRTUAL_CD, nfit_uuid[NFIT_SPA_PCD]);
  	acpi_str_to_uuid(UUID_NFIT_BUS, nfit_uuid[NFIT_DEV_BUS]);
  	acpi_str_to_uuid(UUID_NFIT_DIMM, nfit_uuid[NFIT_DEV_DIMM]);
  
  	return acpi_bus_register_driver(&acpi_nfit_driver);
  }
  
  static __exit void nfit_exit(void)
  {
  	acpi_bus_unregister_driver(&acpi_nfit_driver);
  }
  
  module_init(nfit_init);
  module_exit(nfit_exit);
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Intel Corporation");
  